4126
J . Org. Chem. 1980,45,4126-4129
Reduction of Aldehydes and Ketones by Sodium Dithionite Johannes G. de Vries and Richard M. Kellogg* Department of Organic Chemistry, University of Groningen, Nijenborgh 16, 9747 AG Groningen, The Netherlands Received March 12, 1980
Conditions have been developed for the effective reduction of aldehydes and ketones by sodium dithionite, Nafi204. Complete reduction of simple aldehydes and ketones can be achieved with excess NafizO4 in H20/dioxane mixtures a t reflux temperature. Some aliphatic ketones, for example, pentanone and 4-heptanone, are reduced only sluggishly under these conditions. Good conversions can be achieved, however, by adding dimethylformamide to the reaction mixture, again held a t reflux. The reductions of 17 compounds are described and the scope of the reaction is discussed. a-Hydroxy sulfinates are suggested as probable intermediates in these reductions.
In 1870 Schutzentierger described the reducing powers of a solution of sodium bisulfite in which zinc turnings had been dissolved.' The reducing substance, which Schutzenberger named sodium hydrosulfite, was isolated and was assigned th,e erroneous formula NaHSO2-H20. This substance, later obtained pure by others,%was shown in fact to be Na2S204,2a-Ccommonly known as sodium dithionite. Over the years sodium dithionite has found many applications. It has achieved commercial importance as a reductant in vat dyeing and as a bleaching agent.3 In biochemistry sodium dithionite is used to prepare the reduced forms of several enzymes, coenzymes, and electron-transfer protein^.^ It can serve as an electron source for the nitrogenase system5 and models thereofU6Organic chemical applicatioris of sodium dithionite include reN-nitroso,lo ductions of diazo,8d i a z ~ n i u m nitros^,^ ,~ and nitro c ~ m p o u n d i s , ~imines,12J3 J~ pyridinium salts,14 oximes (to the amines15-17as well as hydrolysis to the parent carbonyl c~mpound'~), and nitroxides.18 Quinones are reduced to the h y d r o q u i n ~ n e s , ~and J ~ ~vicinal ~ ~ dihalides can be dehalogenated to the corresponding alkenes.21 Under proper circumstances certain aromatic
aldehydes can be converted to a-hydroxy sulfinates.22 Symmetrical sulfones can sometimes be obtained by starting from h a l o g e n i d e ~or ~ ~activated ,~~ alkenes.25 In view of these many applications the scarcity of reports on the reduction of carbonyl groups by sodium dithionite becomes all the more striking. Schutzenberger claimed the reduction of acetone and benzaldehyde with sodium dithionite but gave no experimental details.' The reduction of benzil to benzoin has been twice reported1lJsb and the reduction of cyclohexanone to cyclohexanol in up to 10% yield has been observed as an undesired side reaction in an NADH recycling experiment.26 Owing to considerations arising from other workz7we have reexamined the reduction of carbonyl compounds with sodium dithionite and have developed conditions for the effective reduction of various aldehydes and ketones.% Results and Discussions A. Synthetic Results. The results of reduction of a variety of carbonyl compounds (eq 1)are summarized in 0 cc
I/
R ' C R ~t
H20
-
I ( w oIr Iw~ ' t n c ~cl o ~ o l ~ e i l ~
N ~ ~ s ~ o ~
7',&2
+
-;rgarNc
(1) Schutzenberger, M. P. Ann. Chim. Phys. 1870, 20, 351. (2) (a) Bernthsen, A.; Bazlen, M. Chem. Ber. 1900, 33, 126. (b) Bernthsen, A. Justus Liebigs Ann. Chem. 1881,208,142. (c) Bernthsen, A. Chem. Ber. 1905, 38, 1048. (3) See, for instance: I3aumgarte, U. Tertilueredlung 1967, 2, 896. (4) For examples, see: Lambeth, D. 0.;Palmer, G. J. Biol. Chem. 1973, 248, 6095. (5) Hardy, R. W. F.; Knight, E. Biochim. Biophys. Acta 1966,122,520. (6) Schrauzer, G. N. Arigew. Chem. 1975,87, 579. (7) Grandmougin, E. J. Prakt. Chem. 1907, 76, 124. (8) Denisov, N. T.; Solov'eva, S. A,; Shilov, A. E. Kinet. Katal. 1971, 12, 579. (9) (a) Grandmougin, E. Chem. Ber. 1907,40, 422; (b) 1907,40, 858. (c) Methoden Org. Chem. (Houben-Weyl),4th Ed. 1957, Band XI/l, 140. (10) Overberger, C. G.; McGill, E. V.; Anselme, J. P. J. Am. Chem. SOC. 1969, 91, 687. (11) (a) Grandmougin, E:.Chem. Ber 1906,39,3561; (b) 1906,39,3929. (12) Hawthorne, J. 0.;IMihelic, E. L.; Morgan, M. S.; Wilt, M. H. J . Org.Chem., 1963, 28, 2831. (13) Pojer, P. M. Austr. J . Chem. 1979, 32, 201. (14) Eisner, U.; Kuthan, J. Chem. Reu. 1972, 72, 1. (15) Ferris, J. P. U S . Patent 3670007; Chem. Abstr. 1972, 77,100866. (16) Treibs, A,; Schmidt, R.; Zinsmeister, R. Chem. Ber. 1957, 90,79. (17) Smith, L. I.; Schubert, W. M. J. Am. Chem. SOC.1948, 70,2656. (18) (a) Haddadin, M. J.; Alkaysi, H. N.; Saheb, S. E. Tetrahedron 1970,26, 1115. (b) Zahn, G. E.; Rawdaw, T. N. Chelhot, N. C.; Issidorides, C. H. Ibid. 1974, 30, 659. (19) Basalkevich, E. D.; Cherepenko, T. I.; Vysatskii, N. N.; Shapovalenko, V. F.; Svishchuk, A . A. Fiziol. Akt. Veshchestua 1971,174; Chem. Abstr. 1972, 77, 61449. (20) Furusawa, M.; Iwastdti, S.;Matsumura, Y. Nippon Kagaku Kaishi 1974, 2228; Chem. Abstr. 1975, 82, 38271. (21) Kempe, T.; Norin, T.; Caputo, R. Acta Chem. Scand., Ser. B 1976, 30. 366.
0022-3263/80/1945-4126$01.00/0
prodats
(1)
R' = alkyl, aryl; R Z = alkyl, aryl or H Table I. For satisfactory yields to be obtained, the aqueous reaction medium must be mildly basic to prevent too rapid decomposition of Na2S204,which is sensitive to acid (see below). Sodium bicarbonate works best. The reaction temperature must not be lower than 85 " C ; for the solvents used reflux temperature is most convenient. At lower temperature little or no reaction occurs. A cosolvent such as dioxane can be used to increase the solubility of the organic compound. It is advisable to work under nitrogen to prevent air oxidation of Na2S20z9and to add the NazS204in portions to minimize its spontaneous decomposition in aqueous solution to chiefly thiosulfate and s ~ l f i t e . ~ ~ ~ ~ ~ (22) (a) Bazlen, M. Chem. Ber. 1905, 38, 1057; (b) 1909, 42, 4634. (23) Wellish, E.; Gipstein, E.; Sweeting, 0. J. J . Polymer Sci. Part B-2 1964, 35. (24) Matsuo, K.; Kobayashi, M.; Minato, H. Bull. Chem. Soc. J p n . 1970, 43, 260. (25) (a) Kerber, R., German Patent 1122941; Chem. Abstr. 1962,57, 8443~.(b) Kerber, R. German Patent 1097 434; Chem. Abstr. 1961,56, 1351a. (c) Kerber, R.; Starnick, J. Chem. Ber. 1971, 104, 2035. (26) Jones, J. B.; Sneddon, D. W.; Higgins, W.; Lewis, A. J. J . Chem. SOC.,Chem. Commun. 1972,856. (27) (a) de Vries, J. G.; Kellogg, R. M. J . Am. Chem. SOC.1979, 101, 2759. (b) Kellogg, R. M.; van Bergen, T. J.; van Doren, H.; Hedstrand, D.; Kooi, J.; Kruizinga, W. H.; Troostwijk, C. B. J . Org. Chem. 1980,45, 2854. ~ ~. . . (28) Preliminary communication: de Vries, J. G.; van Bergen, T. J.; Kellogg, R. M. Synthesis 1977, 246. (29) See, for instance: Creutz, C.; Sutin, N. Inorg. Chem. 1974, 13, 2041. 0 1980 American Chemical Society
J . Org. Chem., Vol. 45, No. 21, 1980 4127
ReductZionof Aldehydes and Ketones
Table I. Reductions of Aldehydes and Ketones to Alcohols with Na,S,O, entry no. 1
2 3 4 5 6 7 8a b 9a b 10 1l a b 12a b 13a b 14 15a b 16a b 17 18
substrate
product
solvent
n-hexanal benzaldehyde 2-fury1 aldehyde cyclohexanone 4-tot-butylcyclohexanone adamantanone camphor 4-heptanone
benzyl alcohol 2-fury1 alcohol cyclohexanol 4-tert-butylcyclohexanol(cisitruns = 1 3 / 8 7 ) 2-adamantanol n o reaction owing t o sublimation 4-heptanol
2-pentanone
2-pentanol
2-octanorie cyclopenl anone
2-octanol cyclopen tanol
2-norborrianone cycloheptanone
2-norbornanol (exoiendo = 1 7 / 8 3 ) h o r b o r n a n o l (exolendo = 3 1 / 7 9 ) cyclohep tanol
levulinic acid (4-oxopentanoic acid) ace top henone
(4-hydroxypentanoic 1,4-lactone) 1-phenylethanol
benzophenone
diphenylme thanol
4-bromo benzophenone ethyl phenylglyoxalate
(4-bromopheny1)phenylmethanol ethyl mandelate
n-hex ano 1
yield,
H,O H,O-dioxane H2 0 HZ0 H,O-dioxane H -0-d iox ane HfO-dioxane H,O-dioxane H,O-DMF H,O-dioxane H,O-DMF H,O-DMF H ,O -d ioxane H,O-DMF H ,O -d iox ane H,O-DMF H,O-dioxane H,O-DMF H*O H,O-dioxane H,O-DMF H,O-dioxane H,O-DMF H,O-DMF H,Ok
%a
63 84 90 80 94b 97c 25d 69 33d 8 5e 15f 52d 52g 44d lOOh
35d 97d 54' 30d 94 50d 94" 92 24
Isolated yields of pure product unless otherwise indicated; purity was at least 99% as determined by GLC. Isolated as a mixture of cis and trans isomers. The major isomer was obtained in pure form by crystallization from n-heptane and identified as the trans isomer by means of 'H NMR. m p 296-300 "C (authentic sample, m p 296-297.7 "C). Conversions determined by GLC. e An acid-soluble impurity, likely 2-(dimethylamino)pentane,was also formed in 13%yield and was removed by acid washing. 2-( Dimeth 1amino)octane isolated as byproduct in 1 4 % yield. Dimethylcyclopentylamine isolated as byproduct in 48% yield. Isolated as a mixture of exoiendo isomers. Stereochemistry assigned by GLC comparison with product mixture obtained from reduction o f 2-norbornanone with LiA1H,.42 Isolated by continuous extraction with ether. I m p 65.5-66.5 "C (authentic sample, m p 6 9 "C). Reaction carried o u t a t room temperature; complete after 6 h. Apparently considerable hydrolysis occurs.
In hot aqueous solution aldehydes are reduced smoothly to the corresponding ,alcohols (entries 1-3 in Table I) and the carbonyl group of levulinic acid is also readily reduced (entry 14) as are also the carbonyl groups of cyclohexanone, 4-tert-butylcyclohexanone,and adamantanone (entries 4-6). These conditions are not adequate, however, for conversion of other aliphatic and aromatic ketones (Table I, entries 8a, 9a, lla--13a, 15a, 16a). We finally found that the problem of incomplete conversion could be abated by using dimethylformamide (DMF) as a 1:l cosolvent with HzO. Conversions of aromatic ketones under these conditions are virtually complete and the degree of conversion of other ketones is raised considerably. On the other hand the use of cosolvents such as chlorinated hydrocarbons, ethers, alcohols (ethanol, n-propanol, or n-butanol), or tetramethylurea, each as a 1:l mixture with HzO, led only to decreased yields. With DMF as cosolvent some reductive amination reminiscent of that seen in the Leuckart reaction32occurs, especially with methyl ketones and cyclopentanone (footnotes e-g, Table I). Apparently, NazSzO, serves also a reductant in this reaction (eq 2). These amines formed as side products are easily removed, however, by extraction with acid.
were not reduced. Both phenacyl bromide and phenacylphenylmethylsulfonium tetrafluoroborate were reduced to acetophenone at room temperature in H 2 0 with Na2Sz04,but phenacyl benzoate was unaffected under these conditions. B. Mechanism of Reduction. It has long been known that the reaction of Na2SZO4with some aldehydes and ketones under aqueous basic conditions ut room or lower temperature can lead to a-hydroxy sulfinates (1) as shown in eq 3. 0
HZO/bose
t s204'-
?H
I
R'CR~
(3)
s02-
1
For examination of the possibility that a-hydroxy sulfinates could be intermediates in the reductions reported here, la derived from benzaldehyde was synthesized.22b This was added to a refluxing mixture of dioxane-HzO. The reaction product consisted of a 65/35 mixture of benzyl alcohol and benzaldehyde (eq 4). The formation
PH SOzNa
la
The reactions of hla2SZO4 with either benzonitrile or ethyl benzoate led only to hydrolysis of these substrates: diphenylacetylene, N-methylpyrrolidone, and benzoic acid (30) Lister, M. W.; Garcie, R. C. Can. J . Chem. 1959, 37, 1567. (31) Wayman, M.; Lem, W. J. Can. J . Chem. 1970, 48, 782. (32) Bach, R. D. J . Org. Chem. 1968, 33, 1647.
C6H5CHzOH
(4)
of la is known to be r e ~ e r s i b l eexplaining ,~~ the presence of benzaldehyde. The results of the above experiment (33) Yarmolinski, M. B.; Colowick, S. P. Biochim. Biophys. Acta 1956, 20, 177.
4128
J. Org. Chem. Vol. 45, No. 21, 1980
de Vries and Kellogg
provide in our opinion good suggestive evidence for ahydroxy sulfinates im the reactions examined by us. The absence of detectable amounts of pinacolic products in this or other reductions argues against direct transfer of a hydrogen atom to an a-hydroxyalkylradical formed by one electron transfer steps. The reductive decomposition of an a-hydroxy sulfinate (eq 5) involves (possibly concerted) loss of SO2. There is CH
I
A , H20
R'iR'
I
pH
R' R 2 t SO2
I
I
(5)
I
ti
so21
little known of the thermal chemistry of a-hydroxy sulfinates, but precedent for the postulated loss of SO2 can be found in the reported thermal decompositionswith loss of SO2 of several allylic sulfinic acid derivative^.^^-^' There is abundant evidence that Sz02-rapidly fragments in aqueous solution; the kinetic schemes are complicated and the product balances are often not comp l e t e . " ~ ~In~ neutral or mildly acidic solution eq 6 and 7 have been suggested as important contributors to the overall decomposition. The sulfoxylate anion, HS02-, should be sufficiently nucleophilic to lead to the a-hydroxy sulfinate (eq 8) in a manner analogous to bisulfite (HSOc)
-
+ H 2 0 HSOy + HS03HS02- + S20d2- HS03- + S20a2SZO4'-
-
0 HSO2-
II
-t R'CR'
-
(6)
(7)
-+
2
-
0
I
R'GR'
+ so,
3
3+2-1
Conclusions Sodium dithionite, used under the proper conditions, is an effective reagent for the reduction of aldehydes and ketones. The reagent is safe, especially with regard to explosions. Also, water can be used as solvent or cosolvent. These two properties represent advantages over metal hydride reductants. On the other hand, more than stoichiometric amounts are needed for effective reduction and dithionite compares poorly with metal hydrides in hydride equivalents per mole. It may well be, however, that for many carbonyl reductions both on an industrial scale as well as in the laboratory the use of sodium dithionite should be seriously considered. Experimental Section Melting points were determined on a Mettler FP-2 meltingpoint apparatus equipped with a Mettler FP-21 microscope. Elemental analyses were performed in the microanalytical department of this laboratory. Infrared spectra were recorded on a Unicam SP-2OOO infrared spectrophotometer or a Perkin-Elmer 257 grating infrared spectrophotometer. 'H NMR spectra were recorded on a Varian A-60, a JEOL C-GOHL, or a Hitachi Perkin-Elmer R24B spectrometer. Tetramethylsilane (Me,Si) was used as an internal standard. A Varian XL-100 was used for recording the I3C NMR and 100-MHz 'H NMR spectra. Mass spectra were obtained on an AEI MS-902 instrument.
General Procedure for Reduction of Aldehydes and Ketones with Na2S204. A solution of substrate (50 mmol) in 1
(8)
addition. Decomposition as shown in eq 7 could account for the need of roughly 5 equiv of Na2S204necessary for complete reduction of a carbonyl compound. The importance of the reactions of eq 6 and 7 has been questioned, however, chiefly on kinetic grounds.3s Rate expressions for S2042-decomposition usually contain terms one-half order in S2042-.Moreover, the SO2.radical anion (2) is readily detected by electron spin resonance in solutions of decomposing s2042-.39-41 These observations are in accord with eq 9 being an important (reversible) step. The radical anion 2 has also been convincingly implicated as the reductant of various biological material^.^ The reaction steps given in eq 9-11 represent another sequence for the formation of a-hydroxy sulfinates with 2 as the reductant. Ilecomposition as illustrated in eq 5 affords alcohol obtained as end product.
S204*- 2S02-. 2
0
Ill 2 R CR +
(9)
(34) Caughy, W S.;Schellenberg, K. J. Org. Chem. 1966, 31, 1978. (35) Biellmann, J. F.; Callot, H. J. Bull. SOC.Chim.Fr. 1968, 1154. (36) Peterson, P. E.; Brockington, R.; Dunham, M. J. Am. Chem. SOC. 1975, 97, 3517. (37) Masilamani, D.; Rogic, M. M. J . Am. Chem. SOC.1978, 100,4635. (38) (a) Burlamacchi, L ; Guarini, G.; Tiezzi, E. Can. J . Chem. 1971, 49, 1139. (b) Wayman, M ; Lem, W. J. Ibid. 1971, 49, 1140. (39) Hcdgson, W.G.; Neaves, A.; Parker, C. A. Nature (London) 1956, 178, 489. (40) MiliEeviE, H.; Eigenmann, G. Helu. Chim. Acta 1963, 46, 192. (41) (a) Burlamacchi, L.; Casini, G.; Fagioli, 0.;Tiezzi, E. Ric. Scz. 1967,37,97. (b) Burlamacchi, L.; Guarini, G.; Tiezzi, E. Trans. Faraday SOC.1969, 65, 496. (42) For the stereocheinistry of the LiA1H4 reduction of Z-norbornanone, see: Brown, H. C.; Deck, H. R. J . Am. Chem. SOC.1965,87, 5620.
dioxane (175 mL) or DMF for more difficultly reducible substrates is added to water (175 mL) containing NaHC03 (27.5 9). (When DMF was used as cosolvent, in some cases it was necessary to add some more water during the reduction to prevent gel formation.) When no cosolvent is used, the substrate is added neat. Sodium dithionite (12.5 g) is added and the reaction mixture refluxed for 4 h during which time three additional 12.5-g portions of Na2S204 are added. (A total of three 12.5-g portions of Na2S204sufficed for the reductions of benzaldehyde, furfuraldehyde, 4 - t e r t - b ~ tylcyclohexanone, adamantanone, and norbornanone.) The reaction is carried out under an atmosphere of nitrogen. After the mixture cooled to room temperature, water is added until the solution becomes clear and thereafter the solution is extracted with ether (furfuryl alcohol and y-valerolactone were isolated by continuous extraction with ether for 7 and 72 h, respectively). When DMF is used as cosolvent the ether extracts are backwashed twice with water to remove traces of DMF. After the solution is dried (MgS04)and the ether is removed, the products are isolated by either distillation or recrystallization. Identification is based on melting or boiling points, infrared and 'H NMR spectra, and comparison with authentic materials. All reductions were carried out on a 2-mmol scale and for purposes of isolation were also done on a 50-mmol scale. When products were not isolated GLC was used to determine the degree of conversion and/or product ratio. In all those cases a 6 ft X in. Carbowax 20 M on Chromosorb WAW 80-100-mesh column was used. Reduction of 2-Octanone. 2-Octanone (6.41 g, 50 mmol) was subjected to the conditions described above for the reduction of aldehydes and ketones; DMF was used as cosolvent. After workup by the usual procedure, the combined ethereal layers were extracted with two 50-mL portions of 2 N HCl followed by washings with water and saturated NaHC03. The ethereal extract was dried (MgSOJ and ether was removed. The residue was subjected to kugelrohr distillation to give 4.90 g (37.6 mmol, 75% yield) of 2-octanol. The combined acid layers were washed once with ether and then neutralized with a 2 N NaOH solution. The aqueous solution was extracted twice with ether and the combined ethereal layers were washed with water. After the solution was dried
J . Org. Chem. 1980,45, 4129-4135 (Na,SO,) and solvent w,w removed, the residue was subjected to kugelrohr distillation t o give 1.11 g (7.0 mmol, 14% yield) of 2-(dimethylamino)octane: IR (neat) 1050,1110,1160,1275,1385, 1470,2770, 2870,2960 cm-'; 'H NMR (CC14)6 2.13-2.70 (m, 1 H), 2.09 (s, 6 H), 1.24 (br s, 10 H), 0.63-1.20 (m, 6 H); methiodide, m p 232.3-233.1 "C (lit.43mp 240 OC). Anal. Calcd for Cl0HZ3N: C, 76.36; H , 14.74; N, 8-90. Found: C, 76.18; H, 14.75; N, 8.94. S y n t h e s i s a n d Decomposition of S o d i u m B e n z y l h y d r o x y s u l f i n a t e (la). Compound la was synthesized by following Bazlen's method;nb IR (KBr pellet) 655, 690, 955, 1030, 260-3700 cm-' (no absorption due to benzaldehyde carbonyl could be detected). To 40 mL of a refluxing dioxane-H,0 (1:l)mixture was added la (1.5 g, 8.7 mmol). After the mixture was refluxed for 1h under nitrogen, a sample of the mixture was analyzed by GLC (Carbowax, vide supra) and lH NMR. Both benzyl alcohol and benzaldehyde were present in a 65:35 ratio. A solution of la in cold dioxane-water did not contain benzyl alcohol, though a marked amount of benzaldehyde was found to be present in the solution upon GLC analysis; this comes from reversible formation of the a-hydroxy sulfinate. Reduction of Phenacyl Bromide w i t h Na2S204.A solution of phenacyl bromide (400 mg, 2 mmol) in 7 mL of ether was added t o a solution of 1.10 g of NaHC03 in 7 mL of H,O; 2.00 g of Na2SzO4was added and the mixture was stirred under nitrogen for 6 h. The layers were separated and the aqueous layer was extracted with ether. The combined ethereal extracts were dried (MgSO,) and the ether as evaporated. The residue was subjected to kugelrohr distillation to give acetophenone (108 mg, 0.9 mmol, 45% yield). R e d u c t i o n o f methylphenacylphenylsulfonium tetrafluoroborate& was carried out as described above for phenacyl bromide. The sulfonium salt was added neat to the mixture because of its insolubility in ether. After 1.5 h the mixture was worked up as usual. Thte sulfonium salt (666 mg, 2.0 mmol) gave 486 mg of liquid residue, the sole constituents of which were acetophenone and thioanisole in a 1:l ratio (maximum theoretical yield 488 mg). The products were identified by 'H NMR and GLC (Carbowax, vide supra). Attempted Reduction of P h e n a c y l Benzoate. Phenacyl benzoate (485 mg, 2.0 mmol) was subjected to the conditions described for the reduciion of phenacyl bromide. After 6 h the reaction mixture was worked up as usual. Starting material was recovered (432 mg, 89%). Attempted Reduction o f Benzonitrile. Benzonitrile (200 mg, 2.0 mmol) WBS subjected to the conditions described for the (43) van Bergen, T. J.; Iledstrand, D.; Kruizinga, W.; Kellogg, R. M. J. Org. Chem. 1979, 44, 4953. (44) Ionescu, C. N.; Ichim, A. Farmacia Bulzarest 1958, 6, 305.
4129
reduction of aldehydes and ketones, except that the amount of Na2S204was doubled. Dioxane was used as cosolvent. After the usual workup benzamide (178 mg, 75% yield) was isolated. The identity of the product was verified by IR, 'H NMR, melting point, and mixture melting point with an authentic sample. Attempted Reduction of Benzoic Acid. Benzoic acid (245 mg, 1.9 mmol) was subjected to the conditions described for reduction of aldehydes and ketones. Extra NaHC03 was added to allow for neutralization of benzoic acid. Dioxane was used as cosolvent. After termination of the reaction the mixture was acidified by addition of sulfuric acid and was worked up as usual. Benzoic acid w&s recovered (232 mg, 95% yield); no benzyl alcohol could be detected in the reaction mixture by GLC (Carbowax, vide supra). Attempted Reduction of N-Methylpyrrolidone. N Methylpyrrolidone (200 mg, 2 mmol) was subjected to the conditions described for reduction of aldehydes and ketones. When the reaction was terminated the mixture was subjected to continuous extraction with ether. N-Methylpyrrolidone was recovered quantitatively. Attempted Reduction of Diphenylacetylene. Diphenylacetylene (365 mg, 2.0 mmol) was subjected to the conditions described for the reduction of aldehydes and ketones with dioxane as cosolvent; thereafter the reaction mixture was analyzed by GLC (Carbowax, vide supra). The only peak present could be attributed to diphenylacetylene. Neither stilbene nor 1,2-diphenylethane was detected in the reaction mixture.
Acknowledgment. W e are grateful to Dr. T. J. v a n Bergen for his advice at the beginning stages of t h i s work. Registry No. l a , 14339-77-6;Na2S204,7775-14-6; 2-(dimethylamino)octane, 7378-97-4; phenacyl bromide, 70-11-1; methylphenacylphenylsulfonium tetrafluoroborate, 34881-63-5; thioanisole, 100-68-5;benzonitrile, 100-47-0;benzamide, 55-21-0; n-hexanal, 6625-1; benzaldehyde, 100-52-7; 2-fury1 aldehyde, 98-01-1; cyclohexanone, 108-94-1;4-tert-butylcyclohexanone, 98-53-3;adamantanone, 700-58-3; camphor, 76-22-2; 4-heptanone, 123-19-3; 2-pentanone, 107-87-9; 2-octanone, 111-13-7;cyclopentanone, 120-92-3; 2norbornanone, 497-38-1; cycloheptanone, 502-42-1; levulinic acid, 123-76-2;acetophenone, 98-86-2; benzophenone, 119-61-9;4-bromobenzophenone, 90-90-4; ethyl phenylglyoxalate, 1603-79-8;n-hexanol, 111-27-3;benzyl alcohol, 100-51-6; 2-fury1 alcohol, 22125-63-9; cyclohexanol, 108-93-0;cis-4-tert-butylcyc1ohexano1, 937-05-3; trans4-tert-butylcyclohexanol,21862-63-5; 2-adamantanol, 700-57-2; 4heptanol, 589-55-9; 2-pentanol, 6032-29-7; 2-octanol, 123-96-6; cyclopentanol, 96-41-3; exo-2-norbornanol, 497-37-0; endo-2-norbornanol, 497-36-9; cycloheptanol, 502-41-0; 4-hydroxypentanoic 1,4-lactone, 108-29-2;1-phenylethanol, 98-85-1; diphenylmethanol, 91-01-0; (4-bromophenyl)phenylmethanol,29334-16-5; ethyl mandelate, 774-40-3; 2-(dimethylamino)pentane. 57303-85-2; dimethylcyclopentylamine, 18636-91-4.
Reactions of the Cyclopropanone Hemiketal Magnesium Salt with Some Nucleophilic Reagents' J a c q u e s S a l a u n , * F a t i m a Bennani, Jean-Claude C o m p a i n , Antoine
Fadel, and Jean Ollivier
Laboratoire des Carbocycles, ERA 316, Uniuersitg de Paris-Sud, 91405 Orsay, France Received February 7, 1980 Cyclopropanol ( 5 ) , 1-(arylethyny1)cyclopropanol(7), l-(3-hydroxypropyl)cyclopropanol derivative 10, 1-(2propyny1)cyclopropanol (14), cyclopropanone cyanohydrin (19), 1-(aminomethy1)cyclopropanol(2 1) derivatives, benzylidenecyclopropanes 32, and ethyl cyclopropylideneacetate (38) have been prepared from the magnesium salt of cyclopropanone hemiketal3. 3-Cyclopropylidene-l-propanol(l2) and 3-cyclopropylidene-1-propyne(16) have been obtained from the cyclopropanols 10 and 14, respectively. Some reactions of this new synthon were specific. On the other hand, 3 did not undergo the nucleophilic addition of sulfur and nitrogen ylides; it underwent oxidizing ring opening with BrZnCHzCOOEt and induced the decomposition of diazomethane.
The f o r m a t i o n of cyclopropanone f r o m k e t e n e and d i a z o m e t h a n e i n i n e r t solvent at -78 "C has been proven 0022-3263/80/1945-4129$01.00/0
spectroscopically.2~3 But, i n s p i t e of i t s considerable interest, this three-membered-ring ketone is not sufficiently
0 1980 American Chemical Society
